CVE-2026-55206

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-55206", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-16T16:16:32.627Z", "datePublished": "2026-07-08T20:32:09.905Z", "dateUpdated": "2026-07-09T14:26:55.698Z"}, "containers": {"cna": {"title": "py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()", "problemTypes": [{"descriptions": [{"cweId": "CWE-407", "lang": "en", "description": "CWE-407: Inefficient Algorithmic Complexity", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.7, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"}, {"name": "https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8", "tags": ["x_refsource_MISC"], "url": "https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8"}, {"name": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3", "tags": ["x_refsource_MISC"], "url": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3"}], "affected": [{"vendor": "miurahr", "product": "py7zr", "versions": [{"version": "< 1.1.3", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-07-08T20:32:09.905Z"}, "descriptions": [{"lang": "en", "value": "py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, PackInfo._read() in archiveinfo.py used an O(n^2) cumulative sum pattern for attacker-controlled numstreams values parsed from archive headers, allowing a crafted .7z archive to cause excessive CPU consumption during SevenZipFile.init() before extraction. This issue is fixed in version 1.1.3."}], "source": {"advisory": "GHSA-h4gh-22qq-72r7", "discovery": "UNKNOWN"}}, "adp": [{"references": [{"url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-07-09T14:26:52.381780Z", "id": "CVE-2026-55206", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-09T14:26:55.698Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-55206", "role": "CISA Coordinator", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-09T14:26:52.381780Z"}}}], "references": [{"url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7", "tags": ["exploit"]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-09T14:26:43.451Z"}}], "cna": {"title": "py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()", "source": {"advisory": "GHSA-h4gh-22qq-72r7", "discovery": "UNKNOWN"}, "metrics": [{"cvssV4_0": {"version": "4.0", "baseScore": 8.7, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE"}}], "affected": [{"vendor": "miurahr", "product": "py7zr", "versions": [{"status": "affected", "version": "< 1.1.3"}]}], "references": [{"url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7", "name": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7", "tags": ["x_refsource_CONFIRM"]}, {"url": "https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8", "name": "https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8", "tags": ["x_refsource_MISC"]}, {"url": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3", "name": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3", "tags": ["x_refsource_MISC"]}], "descriptions": [{"lang": "en", "value": "py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, PackInfo._read() in archiveinfo.py used an O(n^2) cumulative sum pattern for attacker-controlled numstreams values parsed from archive headers, allowing a crafted .7z archive to cause excessive CPU consumption during SevenZipFile.init() before extraction. This issue is fixed in version 1.1.3."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-407", "description": "CWE-407: Inefficient Algorithmic Complexity"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-07-08T20:32:09.905Z"}}}, "cveMetadata": {"cveId": "CVE-2026-55206", "state": "PUBLISHED", "dateUpdated": "2026-07-09T14:26:55.698Z", "dateReserved": "2026-06-16T16:16:32.627Z", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "datePublished": "2026-07-08T20:32:09.905Z", "assignerShortName": "GitHub_M"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "py7zr", "vendor": "miurahr", "versions": [{"status": "affected", "version": "< 1.1.3"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, PackInfo._read() in archiveinfo.py used an O(n^2) cumulative sum pattern for attacker-controlled numstreams values parsed from archive headers, allowing a crafted .7z archive to cause excessive CPU consumption during SevenZipFile.init() before extraction. This issue is fixed in version 1.1.3."}, {"lang": "es", "value": "py7zr es una biblioteca y utilidad basada en Python para dar soporte a la compresi\u00f3n, descompresi\u00f3n, cifrado y descifrado de archivos 7zip. Antes de la versi\u00f3n 1.1.3, PackInfo._read() en archiveinfo.py utilizaba un patr\u00f3n de suma acumulativa O(n^2) para valores de numstreams controlados por el atacante, analizados a partir de las cabeceras del archivo, lo que permit\u00eda que un archivo .7z manipulado causara un consumo excesivo de CPU durante SevenZipFile.init() antes de la extracci\u00f3n. Este problema se ha corregido en la versi\u00f3n 1.1.3."}], "id": "CVE-2026-55206", "lastModified": "2026-10-25T17:10:00.197", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-55206", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-07-09T14:26:52.381780Z", "version": "2.0.3"}}]}, "published": "2026-07-08T21:16:49.987", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8"}, {"source": "security-advisories@github.com", "url": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3"}, {"source": "security-advisories@github.com", "url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-407"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "py7zr: py7zr: Denial of Service via crafted .7z archives due to inefficient algorithmic complexity", "id": "2498253", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2498253"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-606", "details": ["A flaw was found in py7zr, a Python library for 7zip archives. A remote attacker could exploit this vulnerability by providing a specially crafted .7z archive. This archive, when processed by the `SevenZipFile.init()` function, triggers an inefficient algorithmic complexity (CWE-407) during header parsing. This leads to excessive CPU consumption, resulting in a Denial of Service (DoS) for any application that opens untrusted .7z archives using py7zr."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2026-55206", "public_date": "2026-07-08T20:32:09Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-55206\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-55206\nhttps://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8\nhttps://github.com/miurahr/py7zr/releases/tag/v1.1.3\nhttps://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"], "statement": "This Moderate severity flaw in the `py7zr` library can lead to a Denial of Service. Applications that utilize `py7zr` to open or process untrusted `.7z` archives are vulnerable to excessive CPU consumption. This occurs due to an inefficient algorithm when parsing specially crafted archive headers, allowing a remote attacker to trigger the resource exhaustion without requiring file extraction.", "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.1.3)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "py7zr", "source": "cna", "vendor": "miurahr"}, "product": "py7zr", "vendor": "miurahr"}], "created": "2026-07-08T21:30:08.285963+00:00", "updated": "2026-08-01T15:45:04.318417+00:00", "vendors": ["miurahr", "miurahr$PRODUCT$py7zr"]}